Method of reinforcing a motorcycle frame during conversion to a motorized tricycle

ABSTRACT

A method of reinforcing an L-shaped motorcycle frame during conversion to a motorized tricycle. The L-shaped motorcycle frame is an inverted L-shape with a horizontal portion and a vertical portion. A tricycle frame is provided having spaced apart side plates with a forwardly and downwardly extending portion which terminates in a mounting attachment. The side plates are fastened to opposed sides of the horizontal portion of the L-shaped motorcycle frame. The mounting attachment is secured to the vertical portion of the L-shaped motorcycle frame. This forms a triangular truss with the forwardly and downwardly extending portion of the side plates of the tricycle frame angled between the horizontal portion and the vertical portion to provide rigid support to the L-shaped motorcycle frame.

FIELD

There is described a method of a motorcycle frame during conversion to a motorized tricycle.

BACKGROUND

It has become popular to convert a motorcycle into a motorized tricycle. For these conversions, a tricycle conversion kit is attached to a pre-existing motorcycle frame of the motorcycle being converted. Some types of pre-existing motorcycle frames are generally of an inverted L-shape. Problems have been experienced of structural damage in the form of stress fractures to the pre-existing inverted L-shape motorcycle frame after tricycle conversion due to increased dynamic loading. What is required is a method of converting a motorcycle into a motorized tricycle without structural damage to the pre-existing motorcycle frame due to increased dynamic loading.

SUMMARY

There is provided a method of reinforcing an L-shaped motorcycle frame during conversion to a motorized tricycle. The L-shaped motorcycle frame is an inverted L-shape with a horizontal portion and a vertical portion. A tricycle frame is provided having spaced apart side plates with a forwardly and downwardly extending portion which terminates in a mounting attachment. The side plates are fastened to opposed sides of the horizontal portion of the L-shaped motorcycle frame. The mounting attachment is secured to the vertical portion of the L-shaped motorcycle frame. This forms a triangular truss with the forwardly and downwardly extending portion of the side plates of the tricycle frame angled between the horizontal portion and the vertical portion to provide rigid support to the L-shaped motorcycle frame.

The triangular truss formed by the combined structure of the L-shaped motorcycle frame and the tricycle frame, prevents bending stresses at potential fracture points on the L-shaped motorcycle frame.

As will be hereinafter illustrated and described the triangular truss forms a right angle triangle, with the forwardly and downwardly extending portion of the side plates of the tricycle frame providing a hypotenuse. It will be appreciated that the triangular truss need not form a right angle triangle to provide rigid support.

As will hereinafter illustrated and described, the tricycle frame forms a motorcycle frame support that supports the L-shaped motorcycle frame from below and laterally confines the motorcycle frame. This is accomplished by spacing the side plates so that they are closely positioned on opposed sides of the motorcycle frame and having a difference in spacing between the side plates and the struts. The difference in spacing forms a shoulder that supports the motorcycle frame from below.

Another problem encountered when converting a motorcycle to a motorized tricycle is twisting loads caused when the motorized tricycle operates with two rear wheels. This twisting load can cause bending of the pivot pin used to attach a tricycle swing arm to the motorized tricycle and it can damage the pivot mount. Even more beneficial result may be obtained when an auxiliary pivot support is provided having an interior surface defining a bushing. The auxiliary pivot support is secured to the mounting attachment to provide additional support to the pivot pin and pivot mount for the tricycle swing arm.

Yet another problem encountered when converting a motorcycle to a motorized tricycle is dynamic stresses. Even more beneficial results may be obtained when an auxiliary shock absorber is secured between an upper shock mount on the tricycle frame and a lower shock mount on a tricycle swing arm. The auxiliary shock absorber is centrally positioned between the side plates of the tricycle frame and centrally positioned between two rearwardly extending portions of the tricycle swing arm. With this auxiliary shock absorber, additional suspension loading caused by the motorized tricycle conversion is directed through the tricycle frame. This isolates the motorcycle rear frame from most of the additional dynamic stresses created by the motorized tricycle conversion.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein:

FIG. 1 is a front perspective view of a combined L-shaped motorcycle frame and a tricycle frame.

FIG. 2 is an exploded perspective view of the combined L-shaped motorcycle frame and a tricycle frame of FIG. 1, showing the motorcycle frame separated from the tricycle frame.

FIG. 3 is a side elevation view of the combined L-shaped motorcycle frame and tricycle frame of FIG. 1.

FIG. 4 is an exploded side elevation view of the combined L-shaped motorcycle frame and tricycle frame of FIG. 3.

FIG. 5 is a rear perspective view of the combined L-shaped motorcycle frame and tricycle frame of FIG. 1, with an auxiliary pivot support.

DETAILED DESCRIPTION

A motorcycle frame generally identified by reference numeral 10, will now be described with reference to FIG. 1 through 5.

Structure and Relationship of Parts:

Referring to FIG. 2, an L-shaped motorcycle frame 10 is an inverted L-shape with a horizontal portion 12 and a vertical portion 14. Motorcycle frame 10 is converted to a tricycle by providing a tricycle frame 16 with spaced apart side plates 18. Shoulders 40 on tricycle frame 16 supports motorcycle frame 10 from below. Referring to FIG. 4, side plates 18 have a forwardly and downwardly extending portion 20 which terminates in a mounting plate 22. Side plates 18 are fastened to opposed sides 24 of horizontal portion 12 of motorcycle frame 10. Referring to FIG. 3, a mounting attachment 26 is attached to vertical portion 14 of motorcycle frame 10 to form a triangular truss 28 with forwardly and downwardly extending portion 20 of side plates 18 angled between horizontal portion 12 and vertical portion 14. This provides rigid support to motorcycle frame 10. Triangular truss 28 forms a right angle triangle with horizontal portion 12 and vertical portion 14 forming two sides of the triangle and forwardly and downwardly extending portion 20 of tricycle frame 16 providing a hypotenuse 32.

Referring to FIG. 1, a pivot pin 34 for a tricycle swing arm 36 is supported by an auxiliary pivot support 38. Auxiliary pivot support 38 has an interior surface, not shown, which defines a bushing and is secured to forwardly and downwardly extending portion 20 of side plates 18. An auxiliary shock absorber 44 is secured between an upper shock mount 46 on tricycle frame 16 and a lower shock mount 48 on tricycle swing arm 36. Shock mount 48 is supported by swing arm support 30. Auxiliary shock absorber 44 is centrally positioned between side plates 18 of tricycle frame 16 and centrally positioned between two rearwardly extending portions 21 of tricycle swing arm 36.

Operation:

Referring to FIG. 2, a motorcycle frame 10 is reinforced during conversion to a motorized tricycle by providing a tricycle frame 16 that is supported from below. L-shaped motorcycle frame 10 is an inverted L-shape with a horizontal portion 12 and a vertical portion 14. Motorcycle frame 16 is supported from below by shoulder 40 of tricycle frame 16. Referring to FIG. 4, tricycle frame 16 has spaced apart side plates 18 which have a forwardly and downwardly extending portion 20 which terminates in mounting plate 22. Tricycle frame 16 and motorcycle frame 10 are attached by attaching side plates 18 of tricycle frame 16 to opposed sides 24 of horizontal portion 12 of motorcycle frame 10. Mounting plate 22 is bolted to mounting attachment 26 of motorcycle frame 10. Referring to FIG. 3, this forms a triangular truss 28 with forwardly and downwardly extending portion 20 with side plates 18 being angled between horizontal portion 12 and vertical portion 14. Triangular truss 28 provides rigid support to motorcycle frame 10 and strengthens an otherwise fracture vulnerable area of motorcycle frame 10. Forwardly and downwardly extending portion 20 of tricycle frame 16 forms a hypotenuse 32 to a right angle triangle formed by triangular truss 28.

Referring to FIG. 1, a pivot pin 34 for tricycle swing arm 36 is supported by an auxiliary pivot structure 38. Auxiliary pivot support 38 has an interior surface, not shown, which defines a bushing and is secured to forwardly and downwardly extending portion 20 of tricycle frame 16. Referring to FIG. 2 and FIG. 5, an auxiliary shock absorber 44 is secured between an upper shock mount 46 on tricycle frame 16 and a lower shock mount 48 on tricycle swing arm 36. Lower shock mount 48 is mounted to swing arm support 30 of tricycle frame 16. Auxiliary shock absorber 44 is centrally positioned between side plates 18 of tricycle frame 16 and centrally positioned between two rearwardly extending portions of tricycle swing arm 36.

In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

The following claims are to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, and what can be obviously substituted. Those skilled in the art will appreciate that various adaptations and modifications of the described embodiments can be configured without departing from the scope of the claims. The illustrated embodiments have been set forth only as examples and should not be taken as limiting the invention. It is to be understood that, within the scope of the following claims, the invention may be practiced other than as specifically illustrated and described. 

1. A method of reinforcing an L-shaped motorcycle frame during conversion to a motorized tricycle, the L-shaped motorcycle frame being an inverted L-shape with a horizontal portion and a vertical portion, comprising: providing a tricycle frame having spaced apart side plates with a forwardly and downwardly extending portion which terminates in a mounting attachment; fastening the side plates to opposed sides of the horizontal portion of the L-shaped motorcycle frame; attaching the mounting attachment to the vertical portion of the L-shaped motorcycle frame to form a triangular truss with the forwardly and downwardly extending portion of the side plates of the tricycle frame angled between the horizontal portion and the vertical portion to provide rigid support to the L-shaped motorcycle frame.
 2. The method of claim 1, wherein the triangular truss forms a right angle triangle, with the forward struts of the tricycle frame providing a hypotenuse.
 3. The method of claim 1, wherein the tricycle frame forms a motorcycle frame support that supports the L-shaped motorcycle frame from below.
 4. The method of claim 1, wherein an auxiliary pivot support having an interior surface defining a bushing is secured to the mounting attachment to provided additional support to a pivot pin for a tricycle swing arm.
 5. The method of claim 1, wherein an auxiliary shock absorber is secured between an upper shock mount on the tricycle frame and a lower shock mount on a tricycle swing arm, the auxiliary shock absorber being centrally positioned between the side plates of the tricycle frame and centrally positioned between two rearwardly extending portions of the tricycle swing arm. 